The computer has greatly affected essentially all forms of information management, including the graphical editing and computer aided design and drafting (CAD) tools. Some simpler geometric modeling computer program products are two dimensional, providing only length and width dimensions of objects, while more complex and powerful computer program products provide three dimensional editing and visualization.
Today, computer aided manufacturing (CAM) applications work integral with CAD applications to ease the design and production of machined parts. To mill parts, numerically controlled (NC), or computer numerically controlled (CNC) machines cut away material from a block of matter in various stages, commonly referred to as rough finishing and fine finishing.
In turning manufacturing, it is essential to control the material removal process in order to attain the desired surface quality, but also to protect the investment in manufacturing tooling. The duty for investment protection implies that the manufacturing engineer is given the CAM system functionality to plan his manufacturing processes accordingly. Usually, the manufacturing process consists of complex machining cycles that comprise a multitude of individual NC-commands for material removal. Consisting of repeated roughing or finish passes at incremental cut depth, these machine cycles, also known as “operations”, require control for the duration of the process where the tool is removing material versus tool life as the critical factor.
In is essential to have the ability to interrupt a machining cycle for a variety of reasons. For example, in areas of turning where extremely hard materials have to be machined (e.g., turbine manufacturing). In another example, the cutting tool may be completely worn out requiring replacement after a certain amount of cutting time has elapsed, while the machining cycle has not yet been finished. And in another example, the user may want to inspect the interim result of a complex operation and interrupt the machine cycle to do so.
Interrupting a cutting cycle manually, by editing the NC-file or the internal tool path as represented in a CAM system requires repetitive and cumbersome work that most often requires a complete rework if changes in the design model or previous manufacturing operations have occurred. Also, approaches supporting a so-called “manual” local return after a user-definable number of roughing or finishing passes, in general, do not provide a satisfactory solution, as cutting passes and time intervals for cycle interruption tend to diverge.
What is needed is a system and method for automatic local return for lathe no-machining cycle interruption.